JP5852511B2 - Optical fiber bundle and optical fiber cable - Google Patents

Description

  The present invention relates to an optical fiber bundle in which a plurality of optical fiber cores are assembled and a plastic tape is spirally wound and bundled, and an optical fiber cable using the same.

Conventionally, it is known that a plurality of optical fiber cores are bundled with a plastic tape to form an optical fiber unit, and a plurality of optical fiber units are covered with a jacket to form an optical fiber cable (for example, Patent Document 1). reference).
In Patent Document 1, polyethylene, polyethylene terephthalate, polyamide, etc. are presented as plastic tapes for bundling a plurality of optical fiber cores, and the tape thickness is 0.03 mm to 0.1 mm, and the tape width is 1.0 mm to 10 mm. Is preferred. It is also disclosed that a plastic tape is attached with a curl to prevent the tape from being unwound after winding.

JP 2007-10917 A

  When an optical fiber bundle (optical fiber unit) is formed by bundling a plurality of optical fiber cores with a plastic tape, the optical fiber core wires are wound with a certain degree of tension so that the optical fiber core wires cannot be unraveled. Further, since a plastic tape having a certain width is used from the viewpoint of visibility for identifying the optical fiber bundle, the cross section of the tape is rectangular. For this reason, when spirally wound around the bundled optical fiber cores, both side edge portions in the tape width direction press against the optical fiber core wires located on the outer peripheral side of the bundle bundle, causing transmission loss. There is a fear.

  Further, after a plurality of optical fiber cores are bundled by spiral winding of a plastic tape to form an optical fiber bundle, a plurality of the optical fiber bundles are assembled to form a cable core, and the outer periphery is shared. It is sometimes used as a multi-core optical fiber cable covered with a jacket. In this case, the edge portion of the plastic tape in the cable presses the optical fiber cores of the adjacent optical fiber bundles, which may cause transmission loss.

  The present invention has been made in view of the above circumstances, and an optical fiber bundle in which transmission loss due to pressing of an edge portion of a plastic tape that bundles optical fiber core wires is reduced, and an optical fiber cable using the optical fiber bundle The purpose is to provide.

An optical fiber bundle according to the present invention is an optical fiber bundle in which a plurality of optical fiber cores are assembled and a plastic tape is wound in a spiral shape, and a plurality of cuts are made in the longitudinal direction of the plastic tape. The cut area and the non-cut area where no cut is made are alternately formed, and a plurality of cuts of the plastic tape are inclined with respect to the axial direction of the optical fiber core. .
The length of the cut area is preferably 50 mm or more and 350 mm or less, and the length of the non-cut area is preferably 10 mm or more and 200 mm or less. Moreover, it is preferable that the sum of the length of the cut area and the length of the non-cut area is 500 mm or less.
A plurality of the above optical fiber bundles can be bundled to form an optical cable core, and the optical cable core can be covered with a jacket to form a low-loss optical fiber cable.

  According to the present invention, since the cut area of the plastic tape has no edge portion, an increase in transmission loss with respect to the optical fiber core wire is suppressed, the non-cut area maintains the tape shape, and the visibility of the optical fiber bundle is improved. And workability can be ensured as before.

It is a figure which shows an example of the optical fiber bundle and plastic tape by this invention. It is a figure which shows an example of the optical fiber cable by this invention. It is a figure which shows the evaluation result of this invention.

  An outline of an optical fiber bundle according to the present invention will be described with reference to FIG. In the figure, 10a and 10b are optical fiber bundles, 11a is an optical fiber ribbon, 11b is a single fiber ribbon, 12 is a plastic tape, 12a is a cut area, 12b is a non-cut area, 13 is a cut, and 13a is a cut. Indicates a piece of split tape.

  An optical fiber bundle 10a shown in FIG. 1A is an example of a 20-core optical fiber bundle in which five optical fiber tape cores 11a are stacked and bundled with a plastic tape 12. As the optical fiber tape core 11a, for example, a general optical fiber core wire having a coating outer diameter of 0.25 m arranged in a parallel line and formed into a tape shape by batch coating can be used.

  An optical fiber bundle 10b shown in FIG. 1B is an example of an optical fiber bundle in which a plurality of single optical fiber core wires 11b (eight in the illustrated example) are bundled with a plastic tape 12. As the optical fiber core 11b, for example, an optical fiber core having a coating outer diameter of 0.5 μm can be used.

  The plastic tape 12 of the optical fiber bundles 10a and 10d is made of a plastic material such as polyethylene, polyethylene terephthalate, polyamide, or nylon 12. The tape width is about 1 mm to 10 mm similar to the conventional one, and preferably about 1.5 mm to 7.5 mm.

In the present invention, as shown in FIG. 1 (C), the cut region 12a in which a plurality of cuts 13 are formed in the tape width direction on the plastic tape 12 and the non-cut region 12b in which the cuts 13 are not formed are alternately arranged. It is characterized by being formed. By making the cut 13, the tape width of the cut region 12 a is divided into narrow divided tape pieces 13 a and a plurality of strings are arranged in parallel. The non-break on region 12 b is in its original tape width, keeping the entire tape as long tape including a cut region 12a, has a function to have a visibility as a tape.

As shown in FIGS. 1A and 1B, the plastic tape 12 is spirally formed so as to bundle a plurality of optical fiber ribbons 11a or a plurality of optical fiber cores 11b. It is wound to be optical fiber bundles 10a and 10b.
In this case, in the string-like and narrow divided tape piece 13a of the cut region 12a, the pressing force against the optical fiber core wire that is in contact is dispersed and reduced in the plurality of tape pieces, and an increase in transmission loss is suppressed.

  Therefore, the longer the cut region 12a is, the more advantageous for suppressing increase in transmission loss. However, the visibility as a tape is lowered, and an optical fiber cable in which a plurality of optical fiber bundles are assembled is attached to the tape. The visibility of the optical fiber bundle due to color and identification is lowered, and it becomes difficult to grasp and the workability to take out from the cable is deteriorated. Therefore, it is preferable that the cut region 12a is 50 mm or more and 350 mm or less from the test results described later.

  In addition, if the unbroken region 12b is long, the visibility of the optical fiber bundle described above is improved and the grip is easy to grip, but the edge portions on both sides of the tape width direction hit the optical fiber core wire, and the increase in transmission loss is suppressed. Disadvantageous. Therefore, it is preferable that this unbroken area | region 12b shall be 10 mm or more and 200 mm or less from the test result mentioned later.

  Further, when the optical fiber cable is branched in the middle and the optical fiber core wire is taken out from the middle of the cable, the length for removing the jacket of the cable is about 500 mm. It is preferable that the area | region 12a and the unbroken area | region 12b exist. That is, if the sum of the cut area 12a and the non-cut area 12b is 500 mm or less, the non-cut area 12b always exists in this range when the cable jacket is removed. The fiber bundle can be easily visually confirmed.

In addition, said plastic tape 12 can be manufactured by making a several cut | interruption (slit) intermittently with a cutter etc. in the width direction of a long tape.
Further, it can be manufactured by arranging thin plastic linear bodies in a line on a plane and intermittently bonding and integrating them. For example, a method is considered in which a plurality of yarns of thermoplastic resin such as polyethylene are arranged and intermittently heated and fused and integrated.

FIG. 2 is a diagram in which a plurality of optical fiber bundles according to the present invention described above are assembled to form an optical fiber cable. For example, 10 optical fiber bundles 10a of 20 cores in FIG. This is an example of a 200-fiber optical fiber cable 20. For example, the optical fiber cable 20 is formed by twisting ten optical fiber bundles 10a and bundling them into a circular cross section using a press-wound tape 22 or the like to form a cable core 21, and a jacket (also referred to as a sheath) 23 on the outer periphery thereof. Constructed by extrusion.
In addition, a tension member 24 such as a steel wire is embedded and integrated in the jacket 23, and a tear string 25 for tearing the jacket 23 in the longitudinal direction is embedded, and a tear string is embedded in the outer surface of the jacket 23. A ridge 26 indicating the position is provided.

  In the state where the optical fiber cable 20 configured as described above is installed underground or aerial, portions of the plurality of optical fiber bundles 10a in the cable are in contact with each other. And in the part which the optical fiber bundle 10a mutually contacts, there exists a possibility that the edge part of the plastic tape 12 which bundles an optical fiber core may push the optical fiber core of an adjacent optical fiber bundle, and may cause a transmission loss.

However, as described above, the plastic tape 12 is pressed against the adjacent optical fiber cores by intermittently providing a plurality of cut regions in the tape width direction to form a string-like tape piece. And increase in transmission loss can be suppressed.
In addition, since there is a non-cut area having a tape shape between the cut areas, the non-cut area can be colored to give visibility and ensure the identification of the optical fiber bundle as before. can do.

  FIG. 3 is a diagram showing an evaluation result obtained by testing the above-described optical fiber bundle and an optical fiber cable using the optical fiber bundle. The sample used for the test was tested with an optical fiber cable produced by twisting 10 of the 20 optical fiber bundles shown in FIG. In addition, the plastic tape of the optical fiber bundle used was a tape width of 2 mm, a tape thickness of 0.2 mm, and formed of polyethylene resin.

  In the test samples 1 to 7, the transmission loss (maximum transmission loss) of any one of the optical fiber cores within the 200 cores of the optical fiber cable is changed to 0.25 dB / km by changing the length of the cut region and the non-break length. Is less than ◯, 0.25 dB / km or more and less than 0.30 dB / km is Δ, and 0.30 dB / km or more is ×. In addition, the case where the workability at the time of taking out a predetermined optical fiber bundle after removing 500 mm in the longitudinal direction of the cable jacket is good, and the case where there is a difficulty in taking out the optical fiber bundle are indicated by Δ.

  The result of the test is as shown in FIG. 3, and Sample 1 was a conventional one having no cut area, and the maximum transmission loss was large. Since the length of the cut region of Sample 4 was as long as 500 mm, the optical fiber bundle was scattered and difficult to take out. In sample 5, the length of the unbroken region was as short as 5 mm, and the maintenance of the tape shape was lowered, and the optical fiber bundle was easily scattered as in sample 4.

In sample 3, the length of the cut area was relatively short, 50 mm, and thus the maximum transmission loss increased somewhat, but was within an allowable range. In sample 6, the length of the unbroken area was relatively long at 200 mm, and thus the maximum transmission loss increased somewhat, but was within the allowable range. Samples 2 and 7 were in a range that satisfied both the maximum transmission loss and the workability of taking out the optical fiber bundle.
From the above test results, it can be said that the length of the cut region with the cut is preferably 50 mm to 350 mm, and the length of the non-cut region without the cut is preferably 10 mm to 200 mm.

DESCRIPTION OF SYMBOLS 10a, 10b ... Optical fiber bundle, 11a ... Optical fiber ribbon, 11b ... Single core optical fiber, 12 ... Plastic tape, 12a ... Cut area, 12b ... Non-break area, 13 ... Cut, 13a ... Divided tape piece 20 ... optical fiber cable, 21 ... cable core, 22 ... presser tape, 23 ... jacket, 24 ... tension member, 25 ... tear string, 26 ... ridge.

Claims (5)

An optical fiber bundle in which a plurality of optical fiber cores are assembled and a plastic tape is spirally wound and bundled,
A cut region in which a plurality of cuts are made in the longitudinal direction of the plastic tape and a non-cut region in which no cuts are made are alternately formed, and the plurality of cuts in the plastic tape are formed on the optical fiber core wire. An optical fiber bundle characterized by being inclined with respect to the axial direction .   2. The optical fiber bundle according to claim 1, wherein the cut region has a length of 50 mm to 350 mm.   3. The optical fiber bundle according to claim 1, wherein a length of the non-break region is 10 mm or more and 200 mm or less.   The optical fiber bundle according to any one of claims 1 to 3, wherein a sum of a length of the cut region and a length of the non-cut region is 500 mm or less.   An optical fiber cable comprising a plurality of optical fiber bundles according to any one of claims 1 to 4 bundled to form an optical cable core, and the optical cable core covered with a jacket.

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